very dissapointed my box went bang today and I wasnt even pushing it hard
3000.00 pounds for 200 miles!! of course a lot of those miles were done a 1/4 mile at a time.
Going to try a dox box now hope it is a LOT stronger.

Jon

 

What casing were you using?
When you say it has gone bang, what has actually broken.
Dog boxes are dog engagement as opposed to synchro so unless you have broken the synchro or will change to a different gearset, why will it be stronger?

 

Wider gears harvey, as it doesnt have the syncros

John, welcome to my world, the only one i havent broken yet is the PPG Dog box. All the others lasted no more than 400 miles/10 drag runs.

Steven

 

is this build related ?? and how much power are you putting through it ??? gazza

 

sometimes i think this is all down to luck and the parts you get.
Some are at the 'upper limit' and others not so.

Snapped a rear diff drive shaft today with 380 x 360 engine and slicks.
Half is still in the diff. Others with more had a great day.

 

Harvey ty754 case, syncro and billet selector rods broke.

gazza19800sti1 700+ HP built by API.

Going to 3.9 diffs and wider gears to save a gear change and dogbox so as to have less bits in the box to break and save a bit in the 1/4 mile, getting terminals in the 140's now

911 welcome to my world LOL after going through 8 rear shafts I went to a R180 rear setup and unobtanium rear shafts and have yet to break a shaft , I do think the CF driveshaft helps cushion the shock to the rear diff a bit as well.

 

Jon,

maybe you should post a bit more detail, so people understand what was happening at the time With a passenger

Also, it would be interesting to know if the syncro broke first, causing the fork to then break ? Syncro's are known to be a weak link, billet steel forks aren't.

Mark.

 

Jon, is that the oem syncros that broke, or the PPG synchto gears?

You broke a billet selector arm? Not even i have managed that yet!

 

Looking at the OEM synchro hubs from my last syncro setup, its a question of what went first!

 

yes I will be clear.
there is in no way anything wrong with the ppg gearset or the build of the box by API.
I had just completed a very low 10's 1/4 mile drag run with a passenger in the car.
I was doing a second run to further tune the progressive nitrous system when it got stuck in gear.
third syncro was getting crunchy for the last few trips to the track and I believe the syncro broke and then the billet selector rod.
At the time of failure the engine was going full tilt with a 75 shot of nitrous at 7500 rpm.
I am actually very happy the engine appears to be a good'n with a lot more potential.
I am looking forward to 100 shot on nitrous and 30-40 psi of boost. I fully expected the tranney to give up if it hadnt it would have meant that I would never make it into the 9's which is my ultimate goal.
I will crack the box in the next cople of weeks and give an update.
Jon

 

Steven, I think you're about to be bumped off your throne

 

too late for that................ I think one or two others better watch their backs

Mark.

 

congrats.. broken dccd drop gears here you come.

 

Having stripped my dog box down yesterday with Paul and Pat, it would appear i have now managed to break the 5th/Reverse synchro hub!!! Great eh! Glad i decided to get it checked out now, as the straight cut gears were having a good go at mashing the flying particles!